All of modern science, especially astronomy, and physics place humans and earth in a universe which is endless, and one that creates the possibility of alien civilizations. The more of these ideas are accepted by people, the less likely they are to believe in God.
If you believe there is no space, or that the earth is flat, you are then likely to believe in God. And the reason why people reject these ideas so strongly is because if they even accept these possibilities, they admit that the possibility of God’s existence. And if there is a chance that God exists, then there is the possibility that what religion teaches might be true. As part of religious doctrine (not all religions, of course) there is the possibility of hell. And since most people live a life that is against what God would want, it is more psychologically bearable to believe that God does not exist.
Modern society has moved farther away from God generation after generation. We now find ourselves in societies where God and prayer rarely (if ever) cross people’s minds. We believe in what has become acceptable as science, and use it to elevate our own importance in the big scheme of things. Our humility before the grandeur of creation has faded away and has been replaced by vanity, a vanity that continues to grow and push us even further away from God and spirituality.
This path has led us towards degeneracy which would have been unfathomable only a few generations ago. Our society celebrates sodomy, glorifies mental illness (i.e. sexual dysmorphia), and is slowly edging towards accepting pedophilia—look at pictures of the Gay Pride parades across the Unites States and you will see little children in the midst almost-naked men and women.
Those who are entrenched in this type of life do not see anything wrong with it, yet cannot figure out why no matter how much they engage in worldly indulgences the larger the hole in their soul becomes.